Dual band dipole antenna with collinear director



Feb. 27, 1968 s. smows- 3,371,348

DUAL BAND DIPOLE ANTENNA WITH COL LINEAR DIRECTOR Filed Feb. 10. 1965 4 Sheets-Sheet 1 22. A 46 I8 30 34; B

ATTORNEY S. SIMONS DUAL BAND DIPOLE ANTENNA WITH COLLINEAR DIRECTOR Filed Feb 10, 1965 4 Sheets-Sheet 2 I 82 IOI 84 It 86 8| 88 87 I06 I07 IO 12 7O 72 L W an r U 66 78 gm l4 I6 80 /74 26 70 36 28 30 381 7:2 L \v Y 5=\= m 98 99 IOO "Luz II I I m "UK I IIO III II? Fig. 2

INVENTOR.

SYLVAN S IMONS ATTORNEY Feb. 27, 1968 s. SIMONS 3,371,348

DUAL BAND DIPOLE ANTENNA WITH COLLINEAR DIRECTOR Filed Feb. 10, 1965 4 Sheets-Sheet 4 I40 3 a I40 32 I24 I26 34 I I I Q LL I40/ -36 l 38- I40 I28 II'e I30 V I2 II4 I22 I I I. n I

Fig.5

INVENTOR. SYLVAN SIMONS BY Cuggwg aw ATTORNEY United States Patent 3,371,348 DUAL BAND DIPOLE ANTENNA WITH COLLINEAR DIRECTOR Sylvan Simons, Angelus Drive, Glenville, Greenwich, Conn. 06830 Continuation-impart of application Ser. No. 103,004, Apr. 14, 1961. This application Feb. 10, 1965, Ser. No. 433,843

14 Claims. (Cl. 343-807) This is a continuation-in-part of application Ser. No. 103,004, filed Apr. 14, 1961, now abandoned.

This invention relates to an improved high gain, allchannel television antenna array.

A long-standing problem in television reception is the creation of a television antenna that is relatively simple in design yet is efficiently operative to be resonant in the low band of channels 2 to 6 and the high .band of channels 7-13. Since the low band in the frequency range of 54 to 88 megacycles is spaced from the high band of 174 to 216 megacycles the construction of a simplified all-wave TV antenna presents an extremely difficult problem.

In addition, generally speaking, all the antennas that use a pair of dipoles to receive both high and low band VHF television signals have a half-wave high band dipole constituted of two quarter-wave conductors arranged colinearly. This high frequency dipole is approximately /3 the size of the low frequency dipole and therefore generates about /3 of the voltage traversing the low frequency dipole when subject to otherwise identical conditions. This problem is further compounded when it is considered that the propagation characteristics of the high band is poorer, and the transmission lead wire and the sensitivity of the TV receiver on the high band is weaker. In most TV antenna constructions parasitic elements are included on socalled all-channel TV antennas to increase the gain on these high channels, but there is a theoretical limitation as to how much gain can be achieved in an antenna by the use of parasitics. In practice, the theoretical amount of gain is nowhere utilized because of mismatch in irnpedances due to the parasitic elements lowering the impedance of the dipole.

' In accordance with the disclosure of applicants present invention, the aforesaid problems have been overcome and a relatively simple construction for a high gain broad band TV antenna has been achieved.

An object of' present invention is to provide a full wave dipole of the high frequency band constituted of two half wave conductors separated by such distance that the length of conductor from center of antenna to the outermost extremity of heretofore mentioned half wave conductor will form a quarter wave conductor in the low TV band. It is a further object of the present invention to separate the half wavelength conductors on the high band by a director which physically supports the conductors but is electrically isolated therefrom. This director provides director action for the inboard conductors and further strengthens the received signal.

Another object of the present invention is to provide a broad-band TV antenna which is reliably effective for the purposes intended.

. The above and other features, objects and advantages of the present invention will be fully understood from the following description considered in connection with the accompanying illustrative drawings.

FIG. 1 is a top plan view of a television antenna array constructed in accordance with the present invention.

- FIG. 2 is a top plan view of an alternative construction illustrating a broad band antenna of the end-fire type.

FIG. 3 is a top plan view of a modification of my present invention including cross-phased connections for the dipoles. I

3,371,348. Patented Feb. 27, 1968 FIG. 4 is a top plan view of an alternate construction in accordance with the present invention.

FIG. 5 is a top plan view of a combination VHF-UHF antenna constructed in accordance with the principles of the present invention and FIG. 6 is a top plan view of a modification of the present invention for VHF television reception incorporating wire paddles.

Referring now to FIG. 1 of the drawings, the antenna array constructed in accordance with present invention is mounted on a boom 10 secured to a conventional TV antenna. mast 12 by means of a U-bolt 14 and saddle clamp 16. Secured to the boom 10 by metallic bracket 18 and insulating bracket 20 is the unit constituting an ail-Wave dipole and referred to generally by the numeral 22. The all-wave dipole includes high frequency conductors 24 and 26, a director element composed of conductors 28 and 30 located between the high frequency conductors 24 and 26 and physically supporting them in spaced relationship. The director element is electrically isolated from the high frequency conductors by means of insulators 32 and 34. The all-wave dipole further includes connectors 36 and 38, inboard conductors 40 and 42 and a lead-in wire 44 secured to the inner ends of the inboard conductors 40 and 42 respectively. Connectors 36 and 38 are of a length approximating .1 wavelength as this is widely used in director to dipole spacing for maximum antenna gain. (See ARRL antenna book, ninth edition, page 156).

When operating on the high band television channels generally in the range of 174 to 216 megacycles, high frequency conductors 24 and 26 are of such a length that each is half wave resonant at the design frequency, thereby making a full wave dipole. The director element composed of conductors 28 and 30 connected by metallic bracket 18 reinforces the signal to be picked up by the inboard conductors 40 and 42. It is preferably tuned, (adjusted in length to operate) as a director at the highest channel to be received. As stated above, the director conductors 28 and 30 serve additionally as a mechanical support for conductors 40 and 42 form a common T Match which mum gain. Connectors 36 and 38 together with inboard conductors 40 and 42 form a common Tee Match which is a Well-known expedient in the art.

One end of each of the connectors 36 and 38 are fixed to conductors 24 and 26 at selected positions A and B. These positions are chosen in accordance with the impedance value desired for the antenna array. Since the impedance of a relatively small diameter, full wave dipole at its extremities is in the order of thousands of ohms and the impedance at its center is 72 ohms, any value between these two extremes may be obtained by the proper selection of points A and B. For television reception generally 300 ohms impedance is desired. If parasitic elements are used for the purpose of increasing gain and front to back ratio, this selection would be made with such parasitics in place, inasmuch as their use generally lowers the dipole impedance. Forward of the all-wave unit 22 is a high frequency director consisting of conductors 46 and 48 connected together by a metallic bracket 50. This director is preferably tuned (adjusted in length to operate) at the highest channel to be received. To the rear of the all-wave unit 22 is a reflector formed by the conductors 52 and 54 which are fastened together by metallic bracket 56. This reflector is preferably tuned (adjusted in length to operate) at the lowest frequency of the high channel band to be received. To the rear of the aforesaid reflector is another reflector constituting conductors 58 and 60 together with a loading stub 62 and an insulated bracket 64. This reflector forms the low frequency reflector to reinforce the signal and is preferably adjusted to the lowest frequency to be received, the loading stub permitting use of shorter conductors than are otherwise necessary.

When operating on the low frequency band, conductors 24 and 26 are no longer resonant by themselves. How ever, conductors 24 and 40 with connector 36 form a quarter wave length element resonant in the low frequency band as does opposite conductors 26 and 42 with connector 38 to form a half wave dipole resonant in the low frequency band. The dual band dipole is tuned to low band design frequency by the selection of lengths of conductor 40 and insulator 32 together with opposite con ductor 42 and insulator 34 to provide the end to end length between conductors 24 and 2 6 necessary for resonance. Connectors 36 and 38 will be approximately of the wavelength at which the director composed of conductors 28 and 30 is tuned. By tuned or tuning an element it is meant that its length is adjusted so that it will be near but not necessarily at resonance. The exact length will be such that it will provide the maximum amplitude of received signal. Although this maximum will be at resonance in the case of a dipole element, it will be slightly removed from resonance when used either as a reflector or director, as is well known in the art of tuning a yagi antenna.

An antenna constructed in accordance with the present invention has the following dimensions:

Inches Length of conductors 46 and 48 12 /2 Length of conductors 24 and 26 29 Length of conductors 28 and 30 12% Length of conductors 40 and 42 Length of conductors 52 and 54 16% Length of conductors 58 and 6t) 48 Loading stub 62, 17 inches overall.

FIG. 2 is an alternate construction of the present invention shown in FIG. 1 in which like parts bear the same references. In this case, the all-wave dipoles referred to generally by the numerals 66 and 68 are the same as all-wave dipole 22 of FIG. 1 with the exception that conductors 70 and 72 are added. In dipole 68 the bracket 74 is a metallic bracket while 76 is an insulated bracket.

Conductor 70 together with connector 36 as well as opposite conductor 72 together with connector 38 each are of such a length as to form half wave conductors in the high frequency band so as not to add reactance to half wave conductors 24 and 26. These conductors 70 and 72 add to the fatness of the dipole when operating on both high and low frequency bands, thus providing broader band response. Other characteristics of the dipoles 66 and 68 are the same as for all-wave dipole 22 of FIG. 1. The use of two identical dual band dipoles 66 and 68 in a co-planar relationship and connected together by phasing conductors 78 and 80 form an array commonly known as an End Fire antenna which contributes to the directivity of the array. Elements II, III, V and VI are high band directors and element VII a high band reflector constituted of conductors 82 and 84; 86 and 88; 90 and 92; 94 and 96; and 98 and 100 respectively. The aforesaid conductors are connected to boom 12 by means of metallic brackets 81, 87, 91, 95 and 99 respectively. Boom 10 is fastened to mast '12 by U-bolt 14 and saddle clamp 16. Low band directors I and IV are constituted of conductors 102 and 104 and 106 and 108 respectively, and fastened to boom 10 by insulated brackets 103 and 107. The low band directors I and IV are electrically lengthened by loading stubs 101 and 105 respectively. The use of loading stubs permits the aforesaid directors to be tuned to a desired frequency with shorter conductors than would be necessary without. Reflector VIII incorporates conductors 110 and 112 and is supported by an insulated bracket 111 and is stub loaded at 113.

Representative lengths for an antenna of the aforesaid type constructed to receive on dual band frequencies 54- 88 megacycles and 174-216 megacycles are:

Inches Low frequency directors 102, 104, 106, 108 27 /2 4.- High frequency directors 82, 84, 86, 88, 90, 92,

94, 96 12 /2 High frequency directors 28, 30 12% High frequency reflectors 98, 16% Low frequency reflectors 110, 112 48 High frequency conductors 24, 26 29 High frequency conductors 70, 72 24 Connectors 36, 38 5 T match conductors 40, 42 20 Phasing conductors 78, 80 14 /2 Distance between dual band dipoles VII and VIII measured on centers 15 Distance between dipole director 28, 30 to 2nd director VI 7 Distance between 2nd director VI and 3rd director V 6 Distance between 3rd director V and 1st low frequency director IV 3 Distance between 1st low frequency director IV and 4th high frequency director III 3 Distance between 4th high frequency director III and 5th high frequency director 11 6 Distance between 5th high frequency director II and 2nd low frequency director I 4 Distance between dipole VIII and high frequency reflector IX 12 Distance between high frequency reflector VII and low frequency reflector VIII 13 FIG. 3 illustrates an alternative means of connecting dual band dipoles 66 and 68 which is known as crossphasing. Phasing conductors 114 and 116 are connected in a manner whereby the lead Wire is connected to the dual band dipole 66 which is forwardmost and directed toward the incoming signal. This construction has favorable characteristics in some instances depending upon what channels or frequencies it may be desired to accentuate.

FIG. 4 shows another construction of a dual band dipole. Because the percent variation between extreme frequencies is greater in the low TV band than in the high TV band, a dipole tuned, for example, to channel 4 has a poor response on channel 2. In order to overcome the aforesaid disadvantage a channel 2 dipole may be substituted for one of the previously illustrated dual band dipoles. In this regard, conductors 114 and 116 will act as isolating connectors on the high TV band and their length is chosen to be a quarter wave long so as to offer high impedance at 118 and 120 when folded dipole 122 shows low impedance, which is the case when it is off resonance. On the low TV band, conductors 114 and 116 will offer low impedance to the signal allowing the system to operate as an end-fire antenna.

FIG. 5 illustrates an antenna with a UHF wire dipole commonly used to provide reception in UHF band. This UHF wire dipole, when used with a dual band dipole having a low band VHF folded dipole, results in a combination UHF-VHF three-band antenna. This is illustrated in FIG. 5 in which elements 124 and 126 are UHF directors and elements 128 and 130 are conductors. Conductors 132 and 134 are high-band VHF directors while elements 136 and 138 form a low-band reflector. The wire dipoles 140 extend angularly from the insulators 32 and 34 respectively and are electrically connected to connectors 36 and 38 respectively.

An antenna constructed in accordance with the teachings of FIG. 5 had the following dimensions:

Inches Each leg of wire dipoles 7 /2 Connectors 36 and 38 3 /2 Conductors 128 and 130 7 UHF directors 124 and 126 5 High band VHF directors 132 and 134 12 /2 Isolation connectors 114 and 116 14 /2 Low frequency folded dipole end to end 80 Low frequency folded dipole width 3 Inches Reflector 136 and 138 54 Distance from UHF director to VHF director 3 /2 Distance from folded dipole to reflector 34 Angle between wire dipoles 45 degrees.

It will be noted that in this instance the T Match connects to the innermost extremity of the dipole as is customary for this configuration dipole as the flared end capacity loadsthe conductors to such a degree as to lower the impedance within the vicinity of 300 ohms. This same configuration could be also used as a VHF only dipole by choice of element length as heretofore described.

Variousother configurations may be used on the half wave conductors to either end load or inductively load the dipoles without departing from the spirit of the invention. Also it maybe desirable to depart somewhat from the half wave conductor length as maximum pick-up occurs at .64 wavelength for linear conductors. However, this conductor lengthposes impedance matching problems which accounts for the general selection in the art of integral lengths.

FIG. 6 illustrates another modification of the present invention useful for-VHF television reception. In this construction, insulators 142 and 144 are secured to conductors 146 and 148, the latter being connected to wire paddles 150, wire paddles being used to end load the dipole While I have shown and described the preferred embodiment of my invention, it will be understood that the latter may be embodied otherwise than as herein specifically illustrated or described and that in the illustrated embodiment certain changes in the details of construction and in the arrangement of parts may be made without departing fromthe underlying idea or principle of the invention within the scope of the appended claims.

What I claim is:

1. A wide-band antenna for responding to two widely spaced frequencies comprising a full wave dipole tuned to the higher of the two frequencies including two spaced conductors, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the higher of said two frequencies, a pair of additional conductors, said connecting means connecting corresponding spaced conductors and additional conductors, the total length of each spaced conductor together with the corresponding connecting means and additional conductor defining a dipole tuned to the lower of said two frequencies.

2. A wide-band antenna for responding to two widely spaced frequencies comprising a full wave dipole tuned to the higher of the two frequencies including two spaced conductors, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the higher of said two frequencies, a pair of inboard conductors, said connecting means connecting corresponding spaced conductors to the outer end of each of said inboard conductors, the total length of each spaced conductor together with the corresponding connecting means and inboard conductor defining a dipole tuned to the lower of said two frequencies.

3. A wide-band antenna for responding to two widely spaced frequencies comprising two spaced dipoles each a full wave resonant at the higher of the two frequencies including two spaced conductors, a director element physically supporting but electrically isolated from said spaced conductors, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the higher of said two frequencies, a pair of additional conductors, said connecting means connecting corresponding spaced conductors and additional conductors, the total length of each spaced conductor together with the corresponding connecting means and additional conductor defining a dipole resonant at the lower of said two frequencies, a pair of phasing conductors connecting said spaced dipoles, and a plurality .of directors and reflectors for both the higher and lower of said two frequencies.

4. A wide-band antenna for responding to two widely spaced frequencies comprising a full wave dipole tuned to the higher of the two frequencies including two spaced conductors, a director element located between and supporting said spaced conductors but electrically isolated therefrom, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the higher of said two frequencies, a pair of inboard conductors, said director element reinforcing the signal received by said inboard conductors, said connecting means connecting corresponding spaced conductors to the outer end of each of said inboard conductor defining a dipole tuned to the lower of said two frequencies.

5. A television antenna suitable for use in both the relatively widely spaced low and high frequency bands comprising a substantially co-pl-anar array including a high frequency dipole and a low frequency dipole spaced therefrom, said high frequency dipole comprising a pair of first conductors which are each a half wavelength on the high frequency band and a director located co-axially and between said pair of first conductors and electrically in sulated therefrom, said low frequency dipole having a second pair of spaced conductors which are each half wave on the high frequency band, a pair of connectors connecting said first conductors and second conductors at selected locations for the optimum in signal transmission, and said second conductors being inoperative upon reception of said high frequency band.

6. A television antenna suitable for use in both the relatively widely spaced low and high frequency bands comprising a substantially co-planar array including a high frequency dipole and a low frequency dipole spaced therefrom, said high frequency dipole comprising a pair of first conductors which are each a half wavelength on the high frequency band and a director located co-axially and between said pair of first conductors and electrically insulated therefrom, said director separating said first conductors by a half wavelength, said low frequency dipole having a second pair of spaced conductors which are each half :wave on the high frequency band, a pair of connectors connecting said first conductors and second conductors at selected locations for the optimum in signal transmission, and said second conductors being inoperative upon reception of said high frequency band.

7. A television antenna suitable for use in both the relatively widely spaced low and high frequency bands comprising an array including a high frequency dipole and a low frequency dipole spaced therefrom, said high frequency dipole comprising a pair of first conductors which are each half wavelength on the high frequency band and a director located co-axially and between said pair of first conductors and electrically insulated therefrom, said low frequency dipole having a second pair of spaced conductors which are each half wave on the high frequency band, a pair of connectors, each connecting said first conductors and second conductors, said connections to said second conductors being at one end thereof where substantially infinite impedance occurs whereby said second conductors are inoperative upon reception .of said high frequency band.

8. A wide-band antenna for responding to two widely spaced frequencies as set forth in claim 3 further comprising a lead-in wire connected to the dipole nearest to the incoming signal.

9. A wide-band antenna for responding to two widely spaced frequencies comprising a full wave dipole tuned to the higher of the two frequencies including two spaced conductors, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the higher of said two frequencies, a pair of additional conductors, said connecting means connecting corresponding spaced conductors and additional conductors, the total length of each spaced conductor together with the corresponding connecting means and additional conductor defining a dipole tuned to the lower of said two frequencies, a folded dipole, and connectors connecting said additional conductors to said folded dipole.

10. A wide-band antenna for responding to three widely spaced frequencies comprising a full wave dipole tuned to the highest of the three frequencies including two spaced conductors of wire elements, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the highest of said three frequencies, a pair of additional conductors, said connecting means connecting corresponding spaced conductors and additional conductors, the total length of each spaced conductor together with the corresponding connecting means and additional conductor defining a dipole tuned to the middle of said two frequencies, a low-band folded dipole spaced from said full-wave dipole, and phasing conductors connecting said folded dipole and full-wave dipole.

11. A wide-band antenna for responding to two widely spaced frequencies comprising a full wave paddle-like dipole tuned to the higher of the two frequencies including two spaced conductors, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the higher of said two frequencies, a pair of additional conductors, said connecting means connecting corresponding spaced conductors and additional conductors, the total length of each spaced conductor together with the corresponding connecting means and additional conductor defining a dipole tuned to the lower of said two frequencies.

12. A wide-band antenna for responding to two widely spaced frequencies comprising a full wave dipole resonant at the higher of the two frequencies including two spaced conductors, a director element physically supporting but electrically isolated from said spaced conductors, con necting means being positioned substantially perpendicular to said conductors and of a length approximately .1 wavelength of the higher of said two frequencies, a pair of additional conductors, said connecting means connecting corresponding spaced conductors and additional conductors, the total length of each spaced conductor together with the corresponding connecting means and additional conductor defining a dipole resonant at the lower of said two frequencies.

13. A wide-band antenna for responding to two widely spaced frequencies comprising a full wave dipole tuned to the higher of the two frequencies including two spaced conductors, a director element physically supporting but electrically isolated from said spaced conductors, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the higher of said two frequencies, a pair of inboard conductors, said connecting means connecting corresponding spaced conductors to the outer end of each of said inboard conductors, the total length of each spaced conductor together with the corresponding connecting means and inboard conductor defining a dipole resonant at the lower of said two frequencies.

14. A wide-band antenna for responding to two widely spaced frequencies comprising two spaced dipoles each a full wave dipole tuned to the higher of the two frequencies including two spaced conductors, a director element physically supporting but electrically isolated from said spaced conductors, connecting means being positioned substantially perpendicular to said conductors and of a length approximately 0.1 wavelength of the higher of said two frequencies, a pair of inboard conductors, said connecting means connecting corresponding spaced conductors to the outer end of each of said inboard conductors, the total length of each spaced conductor together with the corresponding connecting means and inboard conduc tor defining a dipole resonant at the lower of said two frequencies, a pair of phasing connectors, and a plurality of directors and reflectors for both the higher and lower of said two frequencies.

References Cited UNITED STATES PATENTS ELI LIEBERMAN, Primary Examiner. 

1. A WIDE-BAND ANTENNA FOR RESPONDING TO TWO WIDELY SPACED FREQUENCIES COMPRISING A FULL WAVE DIPOLE TUNED TO THE HIGHER OF THE TWO FREQUENCIES INCLUDING TWO SPACED CONDUCTORS, CONNECTING MEANS BEING POSITIONED SUBSTANTIALLAY PERPENDICULAR TO SAID CONDUCTORS AND OF A LENGTH APPROXIMATELY 0.1 WAVELENGTH OF THE HIGHER OF SAID TWO FREQUENCIES, A PAIR OF ADDITIONAL CONDUCTOTS, SAID CONNECTING MEANS CONNECTING CORRESPONDINNG SPACED CONDUCTORS AND ADDITIONAL CONDUCTORS, IN TOTAL LENGTH OF EACH SPACED CONDUCTOR TOGETHER WITH THE CORRESPONDING CONNECTING MEANS AND ADDITIONAL CONDUCTOR DEFINING A DIPOLE TUNED TO THE LOWER OF SAID TWO FREQUENCIES. 